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i've come to appreciate, over the past 2 years of heavy Prolog use, that all coding should be (eventually) be done in Prolog. It's one of few languages that is

• dmead 2y ago
  It's taken ages for anything from functional programming to penetrate general use. Do you think uptake of logic stuff will be any faster?
  • johnnyjeans 2y ago
    Prolog (and logic programming in general) is much older than you think. In fact, if we take modern functional programming to have been born with John Backus' Turing Award presentation[1], then it even predates it. Many advancements to functional programming were implemented on top of Prolog! Erlang's early versions were built on top of a Prolog-derived language who's name escapes me. It's the source of Erlang's unfamiliar syntax for more unlearned programmers. It's very much like writing Prolog if you had return values and no cuts or complex terms. As for penetrating general use, probably not without a major shift in the industry. But it's a very popular language just on the periphery, even to this day. [1] - https://dl.acm.org/doi/10.1145/359576.359579 https://dl.acm.org/doi/10.1145/359576.359579
    • dmead 2y ago
      Did you just answer me with chatgpt?
      • hydrolox 2y ago
        definitely not how chat gpt writes
      • exe34 2y ago
        > top of a Prolog-derived language who's name escapes me are you saying we've made a huge leap in LLMs - that they can now admit when they don't know something?
        • diggan 2y ago
          With the right prompting you can get LLMs to output pretty much anything :) > What is the airspeed velocity of an unladen Eurasian blue tit? > I’m not sure. The specific airspeed velocity of an unladen Eurasian blue tit hasn't been studied or widely documented in the same way that birds like swallows have been. It would likely depend on many factors like the bird’s weight, wing shape, and wind conditions. If you’re looking for general information about bird flight or blue tits, I can help with that! /GPT-4o
          • YeGoblynQueenne 2y ago
            GPT-4o is a fan of Monty Python's O.o
            • diggan 2y ago
              Surprised me initially too, but then I remembered it's trained on web content, makes a lot of sense then.
    • dragonwriter 2y ago
      > Erlang's early versions were built on top of a Prolog-derived language who's name escapes me. AFAIK, Erlang was originally implemented in Prolog and the original VM was inspired by the Warren Abstract Machine targeted by some Prolog implementations. It was also inspired by PLEX, but PLEX wasn't a Prolog derivative.
      • johnnyjeans 2y ago
        Oh, apparently I only had half the story. I remembered reading that it was written in a committed-choice derivative of Prolog for concurrency reasons, but apparently that was just a failed experiment that happened early on.[1] [1] - https://erlangforums.com/t/is-the-first-version-of-erlang-written-in-prolog/3986/9 https://erlangforums.com/t/is-the-first-version-of-erlang-wr...
• cmrdporcupine 2y ago
  So why Prolog in particular and not another logic language like Mercury or Oz/Mozart etc?
  • infradig 2y ago
    It's not meant to be taken literally, it refers to any language of logic programming”. Apologies to Monty Python.
  • jfengel 2y ago
    "Prolog" is like Lisp, a wide array of superficially similar languages that actually are quite diverse. Mind you, in that sense, Java and C# are more or less the same language, which has Prolog programmers nodding their heads and Java and C# developers screaming.
    • tannhaeuser 2y ago
      Nope. Prolog is an ISO-standardized language since 1995 and the spec was updated in 2012. Where older "legacy" Prolog implementations such as SWI, YAP, and SICStus are deviating from the standard is generally pretty well-known to Prolog practitioners, and the convener of ISO 13211 actually can verify claims of ISO conformance; for example, [1] is a link to the ISO certification of Quantum Prolog (the web app at [2]). It's true however that people are quick to conflate Prolog with constraint-logic programming libs, "expert systems" (RETE-style forward-chainging systems and other "rule engines"), or random "functional-logic" programming languages. The misunderstanding of Prolog and logic by Lisp programmers has been ongoing since the 1980s, probably because at one point Prolog and Lisp were seen as competing "languages for AI" for some reason even though they have very little in common. [1]: http://www.complang.tuwien.ac.at/ulrich/quantum-prolog/ http://www.complang.tuwien.ac.at/ulrich/quantum-prolog/ [2]: https://quantumprolog.sgml.net https://quantumprolog.sgml.net
      • deleted 2y ago
        [deleted]
      • anthk 2y ago
• tomcam 2y ago
  Is it your thought that for the average programmer Prolog is easier to read and maintain than say Go, C#, or Java?
  • nsxwolf 2y ago
    I found it completely impenetrable in college for all but the simplest problems and I tried to re-read the textbook recently and I didn’t do much better.
    • YeGoblynQueenne 2y ago
      Which textbook was that? I think that Bratko ("Prolog programming for Artificial Intelligence) is probably the most friendly to beginning programmers with a background in more mainstream languages.
  • z5h 2y ago
    I'm surprised at how readable Prolog is. I've played with and seriously used many languages in my career. My experience is that pure functional (done Elm style) is productive and scales well to a larger team. Dynamic stuff like Ruby/Javascript always has more bugs than you think, even with "full" test coverage. I'm not smart enough to make sense of my own Scheme meta-programming when I revisit it months later. I have loads (but dated) experience with Java and it (and peers) are relatively easy to read and maintain. Prolog is very surprising, because it is homoiconic and immensely powerful in metaprogramming, BUT ... the declarative style and execution model reigns in the complexity/readability. A term is just a term. Nothing happens when you create a term. If/when a term is a goal, then you match it with the head of an existing predicate (something you've already coded). So it never gets too messy. Now, the biggest problem with Prolog is that it's so flexible, you'll perpetually be realizing that you could have coded something much more cleanly. So you do that, have less, code, it's nicer, etc. Doing this on a large team might not scale without effort.
    • YeGoblynQueenne 2y ago
      >> I'm not smart enough to make sense of my own Scheme meta-programming when I revisit it months later. Then be smart enough to comment your code :P >> Prolog is very surprising, because it is homoiconic and immensely powerful in metaprogramming, BUT ... the declarative style and execution model reigns in the complexity/readability. Iiiish? This is from one of my yesterday's commit messages: * New look and look-around actions in the Basic Sim Environment allow for looking ahead in eight direction. This does get a liiittle bit complicated, or rather there's the usual millefeuille of abstraction layers on top of abstraction layers all the way down pou that mou ta spasei kapoia stigmi but OK. The Greek-lish interjection says approximately "that is going to bite me in the ass down the line". Because it will. The better I get with Prolog the more I worry nobody will be able to maintain my code but myself, and my future self will hate me with deep, burning passion.
• larodi 2y ago
  Been shouting here and many places for quite a while that CoT and all similar stuff eventually leads to logic programming. So happy I’m not crazy.
  • burntcaramel 2y ago
    COT = Chain-of-Thought https://arxiv.org/abs/2201.11903 https://arxiv.org/abs/2201.11903
  • bbor 2y ago
    You’re in good company — the most influential AI academic of all time, the cooky grandfather of AI who picked up right where (when!) Turing left off, the man hated by both camps yet somehow in charge of them, agrees with you. I’m talking about Marvin Minsky, of course. See: Logical vs. Analogical (Minsky, 1991) https://ojs.aaai.org/aimagazine/index.php/aimagazine/article/download/894/812 https://ojs.aaai.org/aimagazine/index.php/aimagazine/article... …the limitations of current machine intelligence largely stem from seeking unified theories or trying to repair the deficiencies of theoretically neat but conceptually impoverished ideological positions. Our purely numeric connectionist networks are inherently deficient in abilities to reason well; our purely symbolic logical systems are inherently deficient in abilities to represent the all-important heuristic connections between things—the uncertain, approximate, and analogical links that we need for making new hypotheses. The versatility that we need can be found only in larger-scale architectures that can exploit and manage the advantages of several types of representations at the same time. Then, each can be used to overcome the deficiencies of the others. To accomplish this task, each formally neat type of knowledge representation or inference must be complemented with some scruffier kind of machinery that can embody the heuristic connections between the knowledge itself and what we hope to do with it. He phrases it backwards here in comparison to what you’re talking about (probably because no one in their right mind would have predicted the feasibility of LLMs), but I think the parallel argument should be clear. Talking about “human reasoning” like Simon & Newell or LeCun & Hinton do in terms of one single paradigm is like talking about “human neurons”. There’s tons of different neuronal architectures at play in our brains, and only through the ad-hoc minimally-centralized combination of all of them do we find success. Personally, I’m a big booster of the term Unified Artificial Intelligence (UAI) for this paradigm; isn’t it fetch? ;)
• eru 2y ago
  Prolog was a neat exercise, but for practical programming you might want to combine both logical and functional programming. I think 'Curry' does that.
• xelxebar 2y ago
  > over the past 2 years of heavy Prolog use Oh, cool. Mind if I pick your brain a bit? Recently, there was an HN post[0] of a paper that makes a case against pure logic languages in favor of "functional logic" ones, which they exhibit with Curry[1]. The setup argument is that Prolog's specs backtracking, which strongly downlimits it from full SLD resolution, causing fatally sharp edges in real world usage. Being fairly naive to the paradigm, my interpretation is that writing real Prolog programs involves carefully thinking about and controlling the resolution algorithm, which feels very different than straight knowledge declaration. I believe cut/0 is the go-to example. Is that your experience with Prolog in practice? The real meat of the paper, however, is in its case that functional logic languages fully embed Prolog with almost 1-to-1 expressivity, while also providing more refined tools for externalizing knowledge about the intended search space of solutions. Thoughts? How are you using Prolog, logic, or constraint programming? What languages and tooling in this arena do you reach for? What is some of your most hard-earned knowledge? Any lesser-known, but golden, websites, books, or materials you'd like to share? Cheers! [0]:https://news.ycombinator.com/item?id=41816545 https://news.ycombinator.com/item?id=41816545 [1]:https://www.curry-language.org/ https://www.curry-language.org/
  • z5h 2y ago
    So first, let's keep in mind that with no execution model, Prolog is still a "syntax" for Horn clauses. It's still a way to document knowledge. Add SLD resolution and we can compute. The paper (intentionally I presume) orders clauses of a simple predicate to illustrate (cause) a problem in Prolog. But what I actually find is the more time spent in Prolog, the more natural it is to express things in a way that is clear, logical and performant. As with any language/paradigm, there are a few gotchas to be experienced. But generally speaking, SLD resolution has never once been an obstacle (in the past 2 years) of coding. The general execution model of Prolog is pretty simple. The lack of functions actually makes meta-programming much clearer and simpler. A term is just data, unless it's stated as a goal. It's only a valid goal if you've already defined its meaning. So I'd be concerned that Curry gives up the simplicity of Prolog's execution model, and ease of meta-programming. I struggle with the lack of types in Prolog, but also know I can (at least in theory) use Prolog to solve correctness problems in Prolog code. I'm currently using SWI-Prolog. Performance is excellent, it has excellent high-level concurrency primitives[0] (when was the last time you pegged all your cores solving a problem?), and many libraries. I might be one of the few people who has committed to using the integrated editor (PceEmacs) despite being a Vim person. PceEmacs is just too good at syntax highlighting and error detection. At the same time, I'm a huge fan of Markus Triska. His Youtube[1] stuff is mind-expanding (watch all of it, even if you never write Prolog). He has an excellent book online[2]. I admire the way he explains and advances pure monotonic Prolog, and I appreciate the push for ISO conformance and his support for Prologs that that do the same (SWI is not on that list). If you want to learn Prolog, watch all of Markus Triska's videos, read his book, and learn what Prolog could be in a perfect world. Then download SWI-Prolog, and maybe break some rules while getting things done at a blazing speed. Eventually you'll gravitate to what makes sense for you. The Art of Prolog is a classic "must have". Clause and Effect is a good "hit the ground running" (on page 70 you're into symbolic differentiation via term rewriting). 0 https://www.swi-prolog.org/pldoc/man?section=thread https://www.swi-prolog.org/pldoc/man?section=thread 1 https://www.youtube.com/@ThePowerOfProlog https://www.youtube.com/@ThePowerOfProlog 2 https://www.metalevel.at/prolog https://www.metalevel.at/prolog
• hollerith 2y ago
  What is your explanation for Prolog's lack of uptake so far? It has been around for 52 years and got a lot of buzz about 40 years ago because of its usefulness in creating expert systems.
  • upghost 2y ago
    Early systems were largely closed source, proprietary, licensed commercial systems. In some ways Prolog is 52 years old and in some ways it's 5 years old. ...I can relate...
  • tannhaeuser 2y ago
    Not GP, but if Prolog has been around for 52 years, has many implementations old (SICStus/Quintus, SWI, yap, ciao, xsb, eclipse, many more) and new (Scryer, Quantum, Strawberry, Tau, Trealla, ...) then it follows it's not doing so bad after all. I have to say the "expert system" quote comes from lack of insight and perhaps outdated CompSci lecture notes when even at the height of "expert systems" around 1990 or before, Prolog's backward-chaining was seen as the opposite of an expert system's forward-chaining. It may have been the case that what was understood as an "AI language" was anathema following the AI crash around 1988/89 (the original "AI winter"). What also may have contributed to the impression of Prolog becoming less used around 2000-2012 or so is the effect of W3C's/TBL's "Semantic Web" and description logics efforts capturing a portion of the academic and commercial attention in graph and logic databases, as well as in other applied logic domains such as formal verification (in a quite direct sense considering research grants for OWL, etc.)
• dmichulke 2y ago
  > It's one of few languages that is simultaneously a standalone logical formalism, and a standalone representation of computation. (With caveats and exceptions, I know). Would you be able to formulate all those "caveats and exceptions" in Prolog?
  • z5h 2y ago
    For example: the logical core of Prolog along with it's resolution model (for the logical part) are non deterministic (something can have none, one, many solutions) but only one solution is explored at a time. So it's a "meta logical" thing to express something like "the set of solutions for ...". Given that the core of Prolog is Turing complete, you can still get Prolog to compute anything, you might just not have a nice way of declaring it in pure Prolog. Prolog has an interesting history of people discovering ways to express things that are simple, powerful and elegant. And yet despite the simplicity, these ways of expressing things were not immediately evident. DCGs are a prime example.
• shchegrikovich 2y ago
  Have you tried - https://www.minizinc.org/ https://www.minizinc.org/?
• machiaweliczny 2y ago
  Has anyone tried to mine LLM world model via sampling to extract all relations it's believes to be true (like 99%+ certain) into Prolog like clauses. I think this is way to achieve reliable world/domain models in logical sense (non-probabilistic). Probably brain doesn't do it but it could be cool anyway. Seems like good sampler could somehow mine this info by using stuff like I believe that X is true or false for all X imaginable. Then try go generate relations for these etc.
• UltraSane 2y ago
  I'm curious what your thoughts are on this paper [0]Lessons from the evolution of the Batfish configuration analysis tool. Initially they used Datalog but have since migrated to binary decision diagrams for performance reasons, the ability to more accurately model semantics, and more deterministic execution. [0]:https://dl.acm.org/doi/10.1145/3603269.3604866 https://dl.acm.org/doi/10.1145/3603269.3604866